feat: support delete operation

Author: antfu

src/proxy/array.ts

@@ -42,7 +42,11 @@ export function proxifyArrayElements<T extends object>(
         if (typeof key === "symbol") {
           return;
         }
-        const prop = getItem(+key);
+        const index = +key;
+        if (Number.isNaN(index)) {
+          return;
+        }
+        const prop = getItem(index);
         if (prop) {
           return proxify(prop);
         }
@@ -51,7 +55,22 @@ export function proxifyArrayElements<T extends object>(
         if (typeof key === "symbol") {
           return false;
         }
-        replaceItem(+key, literalToAst(value));
+        const index = +key;
+        if (Number.isNaN(index)) {
+          return false;
+        }
+        replaceItem(index, literalToAst(value));
+        return true;
+      },
+      deleteProperty(_, key) {
+        if (typeof key === "symbol") {
+          return false;
+        }
+        const index = +key;
+        if (Number.isNaN(index)) {
+          return false;
+        }
+        elements[index] = literalToAst(undefined);
         return true;
       },
       ownKeys() {

src/proxy/object.ts

@@ -61,6 +61,18 @@ export function proxifyObject<T>(node: ESNode): Proxified<T> {
         replaceOrAddProp(key, literalToAst(value));
         return true;
       },
+      deleteProperty(_, key) {
+        if (typeof key !== "string") {
+          key = String(key);
+        }
+        const index = node.properties.findIndex(
+          (prop) => "key" in prop && "name" in prop.key && prop.key.name === key
+        );
+        if (index !== -1) {
+          node.properties.splice(index, 1);
+        }
+        return true;
+      },
       ownKeys() {
         return node.properties
           .map((prop) => {

test/index.test.ts

@@ -111,7 +111,7 @@ describe("magicast", () => {
     );
   });
 
-  it("parse, update, generate", () => {
+  it("function wrapper", () => {
     const mod = parseCode(`
       export const a: any = { foo: 1}
       export default defineConfig({
@@ -145,4 +145,26 @@ describe("magicast", () => {
       });"
     `);
   });
+
+  it("delete property", () => {
+    const mod = parseCode(`export default { a: 1, b: [1, { foo: 'bar' }] }`);
+
+    delete mod.exports.default.b[1].foo;
+
+    expect(generate(mod)).toMatchInlineSnapshot(
+      '"export default { a: 1, b: [1, {}] };"'
+    );
+
+    delete mod.exports.default.b[0];
+    expect(generate(mod)).toMatchInlineSnapshot(
+      '"export default { a: 1, b: [undefined, {}] };"'
+    );
+
+    delete mod.exports.default.a;
+    expect(generate(mod)).toMatchInlineSnapshot(`
+      "export default {
+        b: [undefined, {}],
+      };"
+    `);
+  });
 });